To recap events briefly: On Monday, John Kerry made a was-it-a-gaffe-or-was-it-genius remark, suggesting the U.S. would call off an attack if Syria agreed to hand over all its chemical weapons. Though the secretary of state immediately dismissed the idea as improbable, Syria and its Russian protectors quickly jumped on it. And so through the course of the day Tuesday, things moved very fast. Even as Obama met with lawmakers on Capitol Hill to lobby for his plan to attack Syria, there were hopeful signs for weapon surrender. Russia created a plan for Syria to give up the weapons. The White House asked the Senate to delay a vote authorizing use of force. Syria asked to join the international treaty banning chemical weapons. The State Department announced that John Kerry would fly to Geneva Thursday to meet with his Russian counterpart, Sergey Lavrov.

All of this may or may not be good news. Pollyannas see a way out for Obama that will prevent further use of chemical weapons in Syria, sidestep a likely embarrassing defeat in Congress, and get the international community moving to stop the slaughter. Cassandras see a White House snookered and outmaneuvered by Bashar al-Assad and Vladimir Putin's stalling techniques.

Either way, it makes Obama's task tonight much harder.

Coming into this week, it was clear what the speech needed to accomplish, even as it seemed nearly impossible to accomplish it all. The president needed to lay out exactly why he wanted to strike Syria -- he has said the purpose is to enforce international norms against chemical weapons. He needed to lay out precisely what he hoped U.S. intervention would achieve. He needed to explain why the U.S. wasn't going to press harder to oust Assad or, alternatively, why doing so would not risk an Iraq-style quagmire. And he needed to rally opinion, both on Capitol Hill and among everyday Americans, from its dismal levels to something more favorable.

What is his task now? It's tough to say.

A bellicose address makes little sense now that there's a diplomatic solution on the table. Obama didn't seem to have the votes in either the House or Senate for military action before today, and as Ezra Klein pointed out this morning, that possibility seems to have made it even easier for members of Congress to oppose the authorization for strikes. Since public opinion tends to follow elected leaders, that could presage even lower general support.

But Obama can't really call it all off and declare victory, either. There are still too many questions about the weapons-handover plan. Past experience suggests it may not be wise to trust the shifty autocrat in Moscow, to say nothing of the Levantine dictator who recently gassed his own citizens. Too celebratory a gloss on the diplomatic progress could set the U.S. up for deeper embarrassment in a day or a week if negotiations fail and Russia or Syria reneges on their promises. Obama could take the explanatory tack, laying out what has happened, but he hasn't shown much appetite for communicating complicated policy concepts to large audiences, preferring to delegate that task to "Secretary of Explaining Stuff" Bill Clinton. This president's mode is uplift.

Who even is Obama's primary audience tonight? If it's Congress, it's not clear what he's calling on them to do. If it's the American public, it's not clear what he's asking them to support, except patient diplomacy -- which means he's come around to the American people's position after a week or so of greater belligerence; that's what they seem to have wanted in the first place. Perhaps Obama is speaking to Syria and Russia, to cajole and show his faith in diplomacy, but if so, he has to deliver a message that also makes sense to an audience stateside.

As the clock ticks down to 9 p.m., one of the few things that's clear is that Obama's timing couldn't have been much worse. The Oval Office address has been planned for days, and the president and his team seem to have expected they would either have a change for a resolute ultimatum (to either Assad of Congress) or a climactic announcement of strikes. Instead, they're left with tenuous progress that's too risky to celebrate and tough to explain -- and probably a large stack of discarded speech drafts in West Wing wastebaskets.